.page-about {
  --about-line: rgba(44, 55, 102, 0.28);
  --about-gap: clamp(20px, 3vw, 36px);
  position: relative;
  isolation: isolate;
  padding-bottom: clamp(40px, 7vw, 88px);
}

.page-about::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background-image:
    linear-gradient(to right, var(--about-line) 1px, transparent 1px),
    linear-gradient(to bottom, var(--about-line) 1px, transparent 1px);
  background-size: 88px 88px;
  -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.75), rgba(0, 0, 0, 0) 62%);
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.75), rgba(0, 0, 0, 0) 62%);
  opacity: 0.55;
  pointer-events: none;
}

.page-about p {
  max-width: 68ch;
  line-height: 1.75;
}

/* ---------- 封面 ---------- */
.page-about .about-cover {
  padding-top: clamp(18px, 3vw, 34px);
}

.page-about .cover-grid {
  align-items: end;
  row-gap: var(--about-gap);
  margin-top: clamp(22px, 4vw, 40px);
}

.page-about .cover-lead h1 {
  margin: 14px 0 18px;
  font-size: clamp(2rem, 5.6vw, 3.6rem);
  line-height: 1.06;
  font-weight: 800;
  letter-spacing: -0.02em;
  max-width: 17ch;
  color: var(--text);
}

.page-about .cover-lead .lead {
  max-width: 52ch;
  color: var(--text);
}

.page-about .cover-facts {
  list-style: none;
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px 14px;
}

.page-about .cover-facts li {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 8px 16px;
  border-radius: var(--r-pill);
  border: 1px solid var(--line-soft);
  background: rgba(18, 21, 31, 0.72);
  font-size: 14px;
  color: var(--muted);
}

.page-about .cover-facts .num {
  font-family: var(--font-mono);
  font-size: 18px;
  color: var(--mint);
}

.page-about .cover-index {
  border-left: 1px solid var(--line-soft);
  padding-left: clamp(16px, 2vw, 26px);
}

.page-about .index-title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .cover-toc {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 6px;
}

.page-about .cover-toc .toc-link {
  display: flex;
  gap: 12px;
  align-items: baseline;
  padding: 9px 12px;
  border-radius: var(--r-md);
  border: 1px solid transparent;
  color: var(--text);
  text-decoration: none;
  font-size: 15px;
  transition: background 0.2s var(--ease), border-color 0.2s var(--ease), color 0.2s var(--ease);
}

.page-about .cover-toc .toc-link:hover,
.page-about .cover-toc .toc-link:focus-visible,
.page-about .cover-toc .toc-link[aria-current="true"] {
  background: rgba(43, 240, 194, 0.08);
  border-color: rgba(43, 240, 194, 0.35);
  color: var(--mint);
}

.page-about .toc-mark {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--mint);
}

.page-about .about-cover-media {
  margin: clamp(26px, 4vw, 48px) auto 0;
  aspect-ratio: 16 / 7;
  border: 1px solid var(--line-soft);
  border-radius: var(--r-xl);
  box-shadow: inset 0 0 70px rgba(43, 240, 194, 0.06);
}

.page-about .about-cover-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

/* ---------- 章节骨架 ---------- */
.page-about .section {
  padding-block: clamp(42px, 6.5vw, 84px);
  border-top: 1px solid var(--line-faint);
  scroll-margin-top: 96px;
}

.page-about .section-num {
  display: inline-block;
  margin-bottom: 14px;
  padding: 4px 14px;
  border-radius: var(--r-pill);
  border: 1px solid rgba(43, 240, 194, 0.35);
  background: rgba(43, 240, 194, 0.07);
  color: var(--mint);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
}

.page-about .section-title {
  margin: 0 0 18px;
  font-size: clamp(1.55rem, 3.4vw, 2.4rem);
  line-height: 1.14;
  font-weight: 800;
  letter-spacing: -0.02em;
  max-width: 24ch;
  color: var(--text);
}

.page-about .measure {
  color: var(--muted);
}

.page-about .sec-grid {
  row-gap: var(--about-gap);
}

.page-about .sec-aside {
  position: relative;
  align-self: start;
  padding: 10px 0 10px clamp(16px, 2vw, 26px);
  border-left: 1px solid var(--line-soft);
}

.page-about .sec-aside::before {
  content: "";
  position: absolute;
  left: -1px;
  top: 0;
  width: 9px;
  height: 72px;
  background: repeating-linear-gradient(180deg, var(--line) 0 1px, transparent 1px 9px);
}

.page-about .aside-kicker {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--mint);
}

.page-about .sec-aside .aside-text {
  margin: 0 0 16px;
  max-width: 30ch;
  font-size: 15px;
  line-height: 1.7;
  color: var(--muted);
}

.page-about .aside-figure {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 30px;
  line-height: 1;
  color: var(--amber);
}

.page-about .aside-caption {
  margin: 6px 0 0;
  max-width: 24ch;
  font-size: 13px;
  color: var(--muted);
}

/* ---------- 三段观察 ---------- */
.page-about .phase-track {
  margin-top: clamp(22px, 4vw, 40px);
  display: grid;
  gap: var(--about-gap);
  grid-template-columns: 1fr;
}

.page-about .phase-card {
  padding: clamp(20px, 3vw, 28px);
  border: 1px solid var(--line-soft);
  border-radius: var(--r-lg);
  background: var(--panel);
}

.page-about .phase-card--2 {
  border-color: rgba(43, 240, 194, 0.32);
  background: linear-gradient(165deg, rgba(43, 240, 194, 0.07), rgba(18, 21, 31, 0.96) 58%);
}

.page-about .phase-card--3 {
  background: linear-gradient(165deg, rgba(74, 27, 51, 0.62), rgba(18, 21, 31, 0.96) 62%);
}

.page-about .phase-tag {
  display: inline-block;
  padding: 4px 14px;
  border-radius: var(--r-pill);
  background: rgba(43, 240, 194, 0.12);
  color: var(--mint);
  font-size: 12px;
  letter-spacing: 0.14em;
}

.page-about .phase-card--3 .phase-tag {
  background: rgba(255, 138, 61, 0.14);
  color: var(--amber);
}

.page-about .phase-title {
  margin: 14px 0 10px;
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text);
}

.page-about .phase-card .phase-text {
  margin: 0;
  max-width: 44ch;
  font-size: 15px;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .phase-list {
  list-style: none;
  margin: 16px 0 0;
  padding: 14px 0 0;
  border-top: 1px dashed var(--line-soft);
  display: grid;
  gap: 9px;
}

.page-about .phase-list li {
  display: flex;
  gap: 10px;
  font-size: 14px;
  color: var(--text);
}

.page-about .phase-list li::before {
  content: "";
  flex: none;
  width: 6px;
  height: 6px;
  margin-top: 8px;
  border-radius: 50%;
  background: var(--mint);
}

.page-about .phase-card--3 .phase-list li::before {
  background: var(--amber);
}

@media (min-width: 900px) {
  .page-about .phase-track {
    grid-template-columns: repeat(3, 1fr);
    align-items: start;
  }
  .page-about .phase-card--2 {
    margin-top: 36px;
  }
  .page-about .phase-card--3 {
    margin-top: 72px;
  }
}

/* ---------- 团队 ---------- */
.page-about .team-grid {
  row-gap: var(--about-gap);
}

.page-about .team-list {
  list-style: none;
  margin: clamp(18px, 3vw, 28px) 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .team-item {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 16px;
  padding: 16px 18px;
  border: 1px solid var(--line-soft);
  border-radius: var(--r-lg);
  background: rgba(18, 21, 31, 0.72);
  transition: border-color 0.2s var(--ease), transform 0.2s var(--ease);
}

.page-about .team-item:hover {
  border-color: rgba(43, 240, 194, 0.4);
  transform: translateX(3px);
}

.page-about .team-idx {
  padding-top: 3px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--amber);
}

.page-about .team-name {
  margin: 0 0 6px;
  font-size: 1.02rem;
  font-weight: 700;
  color: var(--text);
}

.page-about .team-item .team-text {
  margin: 0;
  max-width: 58ch;
  font-size: 14.5px;
  line-height: 1.72;
  color: var(--muted);
}

.page-about .team-side {
  align-self: start;
}

.page-about .team-shot {
  aspect-ratio: 1 / 1;
  border-radius: var(--r-xl);
  border: 1px solid var(--line-soft);
  margin: 0;
}

.page-about .team-shot img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

/* ---------- 版本时间线 ---------- */
.page-about .timeline {
  list-style: none;
  margin: clamp(24px, 4vw, 42px) 0 0;
  padding: 0;
  position: relative;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 10px;
  bottom: 10px;
  width: 1px;
  background: linear-gradient(180deg, var(--mint), rgba(43, 240, 194, 0.12));
}

.page-about .tl-item {
  position: relative;
  padding-left: 40px;
  margin-bottom: 14px;
}

.page-about .tl-item:last-child {
  margin-bottom: 0;
}

.page-about .tl-item::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 24px;
  width: 13px;
  height: 13px;
  border-radius: 50%;
  background: var(--ink);
  border: 2px solid var(--mint);
  box-shadow: 0 0 0 4px rgba(43, 240, 194, 0.12);
  transition: box-shadow 0.25s var(--ease), background 0.25s var(--ease);
}

.page-about .tl-item:hover::before {
  background: var(--mint);
  box-shadow: 0 0 0 7px rgba(43, 240, 194, 0.16);
}

.page-about .tl-card {
  padding: 16px 20px;
  border: 1px solid var(--line-soft);
  border-radius: var(--r-lg);
  background: var(--panel);
  transition: border-color 0.24s var(--ease), transform 0.24s var(--ease), box-shadow 0.24s var(--ease);
}

.page-about .tl-item:hover .tl-card {
  border-color: rgba(43, 240, 194, 0.45);
  transform: translateX(4px);
  box-shadow: 0 14px 32px rgba(0, 0, 0, 0.35);
}

.page-about .tl-ver {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--amber);
}

.page-about .tl-title {
  margin: 8px 0;
  font-size: 1.08rem;
  font-weight: 700;
  color: var(--text);
}

.page-about .tl-card .tl-text {
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.72;
  color: var(--muted);
}

/* ---------- 数据来源 ---------- */
.page-about .data-side {
  align-self: start;
}

.page-about .flow-figure {
  margin: 0;
  aspect-ratio: 3 / 2;
  border: 1px solid var(--line-soft);
  border-radius: var(--r-xl);
}

.page-about .flow-figure img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

/* ---------- 收束区 ---------- */
.page-about .about-next {
  border-top: 0;
}

.page-about .next-panel {
  padding: clamp(26px, 5vw, 56px);
  border: 1px solid var(--line-soft);
  border-radius: var(--r-xl);
  background:
    radial-gradient(120% 140% at 88% 0%, rgba(43, 240, 194, 0.14), transparent 55%),
    linear-gradient(150deg, rgba(36, 27, 69, 0.92), rgba(10, 14, 39, 0.94) 58%, rgba(74, 27, 51, 0.7));
}

.page-about .next-grid {
  margin-top: clamp(22px, 3vw, 34px);
  display: grid;
  gap: 14px;
  grid-template-columns: 1fr;
}

@media (min-width: 760px) {
  .page-about .next-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.page-about .next-link {
  display: block;
  padding: 20px 22px;
  border-radius: var(--r-lg);
  border: 1px solid rgba(233, 238, 249, 0.14);
  background: rgba(10, 14, 39, 0.45);
  color: var(--text);
  text-decoration: none;
  transition: border-color 0.2s var(--ease), transform 0.2s var(--ease), background 0.2s var(--ease);
}

.page-about .next-link:hover,
.page-about .next-link:focus-visible {
  border-color: rgba(43, 240, 194, 0.55);
  background: rgba(43, 240, 194, 0.08);
  transform: translateY(-3px);
}

.page-about .next-link-title {
  display: block;
  margin-bottom: 6px;
  font-size: 1.05rem;
  font-weight: 700;
}

.page-about .next-link-text {
  display: block;
  font-size: 14px;
  line-height: 1.65;
  color: var(--muted);
}

/* ---------- 响应式 ---------- */
@media (max-width: 899px) {
  .page-about .cover-index {
    border-left: 0;
    border-top: 1px solid var(--line-faint);
    padding: 20px 0 0;
  }
  .page-about .sec-aside {
    border-left: 0;
    border-top: 1px solid var(--line-faint);
    padding: 16px 0 0;
  }
  .page-about .sec-aside::before {
    display: none;
  }
  .page-about .about-cover-media {
    aspect-ratio: 4 / 3;
  }
  .page-about .tl-item {
    padding-left: 32px;
  }
  .page-about .timeline::before {
    left: 7px;
  }
  .page-about .tl-item::before {
    left: 1px;
    top: 20px;
  }
}

@media (max-width: 560px) {
  .page-about .cover-facts li {
    font-size: 13px;
    padding: 7px 13px;
  }
  .page-about .team-item {
    grid-template-columns: 1fr;
    gap: 8px;
  }
  .page-about .team-idx {
    padding-top: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    animation: none !important;
    transition: none !important;
  }
}